Apparatus for and method of die forming and perforating pilfer-proof band of closure caps

ABSTRACT

This disclosure relates to a closure cap having a pilfer-proof band wherein the closure cap is formed entirely by a die punching operation, including the perforation thereof to define the pilfer-proof band. The cap is initially die formed with an intermediate shoulder formed in the skirt, after which in a simultaneous operation the upper portion of the cap body is provided with knurling and the lower portion of the cap body or skirt is sheared through the shoulder to define a circumferential line of perforation interrupted by connecting tabs. The shoulder formation is such that when severed, reinforcing curls are provided on opposite sides of the perforation. Another feature of the die is that the knurling is effected by cooperating projections on the die with certain of the projections being in the form of pins.

' United States Patent [1 91 Moller Jan. 14, 1975 [75] Inventor: Jens L.Moller, Westmont, Ill.

[73] Assignee: Continental Can Company, Inc.,

New York, NY.

[22] Filed: Apr. 9, 1973 [21] Appl. No.: 349,435

Related US. Application Data [62] Division of Ser. No. 148,604, June 1,1971, Pat. No.

[52] US. Cl 113/121 A, 72/324, 72/348, 113/1 D, 113/15 A [51] Int. ClB21d 51/00 [58] Field of Search... 113/1 D, 121 A, 15 R, 15 A; 83/695;72/348, 324; 220/48; 215/42 3,455,479 7/1969 Hadley et al 215/423,465,907 9/1969 3,589,544 6/1971 3,601,273 8/1971 Kutcher 215/42Primary ExaminerC. W. Lanham Assistant Examiner.lames R. Duzan Attorney,Agent, or Firm-Diller, Brown, Ramik & Wight [57] ABSTRACT Thisdisclosure relates to a closure cap having a pilferproof band whereinthe closure cap is formed entirely by a die punching operation,including the perforation thereof to define the pilfenproof band. Thecap is initially die formed with an intermediate shoulder formed in theskirt, after which in a simultaneous operation the upper portion of thecap body is provided with knurling and the lower portion of the cap bodyor skirt is sheared through the shoulder to define a circumferentialline of perforation interrupted by connecting tabs. The shoulderformation is such that when severed, reinforcing curls are provided onopposite sides of the perforation. Another feature of the die is thatthe knurling is effected by cooperating projections on the die withcertain of the projections being in the form of pins.

7 Claims, 8 Drawing Figures sum 2 0F 5 PATENTED JAN 1 4 I975 PATENTEDJAN] 4l975 SHEET 30F 3 Ill, "IIIIII- A W///// 9 I. 4 y 3 I 2 I APPARATUSFOR AND METHOD OF DIE FORMING AND PERFORATING PILFER-PROOF BAND OFCLOSURE CAPS This application is a division of my copending applicationSer. No. 148,604, filed June I, 1971, now U.S. Pat. No. 3,746,202.

This invention relates in general to new and useful improvements incontainers, and more particularly to closure caps of the type havingpilfer-proof bands, an apparatus for and method of making same.

BACKGROUND OF THE INVENTION It is well known to provide closure caps,each having a pilfer-proof band integrally connected to the lower edgeof the skirt thereof by frangible tabs and wherein in the application ofsuch closure cap to a bottle, the pilfer-proof band is interlocked withthe bottle neck and the connecting tabs must be broken in order tounthread the closure cap from the bottle.

The pilfer-proof band is formed as an extension of the skirt of theclosure cap and is separated therefrom except for the connecting tabs byperforating the skirt of the closure cap. This is normally accomplishedin a rolling operation which requires rotation of either the closure capor the perforating die.

The closure caps are also normally provided with a roughened peripheralconfiguration, normally in the form of knurling, in order to facilitatethe turning thereof. This knurling is normally also performed byrotating the closure cap and requires separate tooling from thatutilized in perforating the closure cap to form the pilfer-proof band.

It is also well known that closure caps are formed from flat sheet blankmaterial by a series of punch and die operations. These punch and dieoperations, of necessity, require different mechanism from that whichhas heretofore been utilized in the knurling and perforating of theclosure cap.

SUMMARY OF THE INVENTION In accordance with this invention, it isproposed to provide a punch and die assembly which is capable ofsimultaneously forming in a single compound operation both the desiredknurling and perforation of a closure cap.

In accordance with this invention, it is proposed that compound,reciprocating punch and die sets be provided for effectingtheperforation and knurling of closure caps wherein the die sets may beincorporated with other die sets utilized in blanking and forming theclosure caps so that closure caps may be formed in a series ofsimultaneously acting punching operations.

In accordance with this invention, in the formation of a closure cap,the closure cap is provided with an elongated skirt with the lowerportion of the skirt being set off by an outwardly sloping shoulder.Thereafter, during the punching sequence, the die sets formed inaccordance with this invention will function to engage and sever theshoulder except for a plurality of narrow circumferentially spacedportions, and thereafter move the partially severed skirt portion orpilfer-proof band axially with respect to the remainder of the closurecap so as to provide a spacing between the two except for the remainingunperforated areas which are in the form of connecting tabs.

Another feature of this invention is that the shoulder formation is suchthat when it is severed intermediate its edges, the lower edge of theskirt of the closure cap and the upper edge of the pilfer-proof bandhave reinforcing flanges or curls.

The closure cap, having already been shaped before arriving at theperforating and knurling die station, may be simultaneously knurled andperforated. Accordingly, the die sets provided in accordance with thisinvention have formed in the upper part thereof suitable means foreffecting the knurling of the upper portion of the closure cap in apunching operation, which punching operation is performed simultaneouslywith the perforating operation.

A particular feature of the perforating and knurling die sets is thatthe punch of the upper die set is provided with projections which causeradial inwardly directed indentations in the closure cap, and theseprojections are formed as hardened pins which are readily insertable andreplaceable in the punch.

The net result of the compound perforating and knurling punch and diesets includes a novel method of perforating and knurling closure capsand a novel closure cap which is of a reinforced construction.

With the above and other objects that will hereinafter appear, thenature of the invention will be more clearly understood by reference tothe following detailed description, the appended claims and the severalviews illustrated in the accompanying drawings.

IN THE DRAWINGS:

FIG. 1 is an exploded elevational view taken through the die sets withparts broken away and shown in section and with a preformed closure capin position to be operated on by the die sets.

FIG. 2 is a fragmentary bottom plan view of the upper die set takenalong the line 2-2 of FIG. 1 and shows further the details thereof.

FIG. 3 is a plan view of the lower die set taken along the line 3-3 ofFIG. 1 and shows further the details thereof.

FIG. 4 is a fragmentary vertical sectional view taken through the diesets in its fully telescoped position and shows the same at theconclusion of the knurling and perforating action thereof.

FIG. 5 is a fragmentary horizontal sectional view taken along the line5-5 of FIG. 4 and shows specifically the details of the knurlingoperation.

FIG. 6 is a fragmentary vertical sectional view taken along the line 6-6of FIG. 5 and shows the specific supporting of the closure cap in theknurling area during the knurling operation.

FIG. 7 is a fragmentary vertical sectional view taken along the line 77of FIG. 4 and shows the manner in which the closure cap is supported inthe area of the connecting tabs during the perforating operation.

FIG. 8 is a fragmentary sectional view taken through another die setshowing the closure cap being trimmed as a final step in the formationof the closure cap.

Referring now to the drawings in detail, it will be seen that there isillustrated in FIG. 1 a partially formed closure cap in accordance withthis invention, the closure cap being generally identified by thenumeral 10. The closure cap 10 includes an end wall portion 11 and abody portion 12. The body portion 12 is cylindrical and is in the formof a skirt of which a major part is identified by the numeral 13. Thebody portion 12 includes a skirt extension 14 which is connected to thebody part 13 by an outwardly offset shoulder 15 which is generallyS-shaped in cross section. The skirt extension 14 has integrallyconnected to the lower edge thereof an outwardly directed flange 16.

The end wall portion 11 includes an end panel 17 and a generally steppedportion 18 which is integrally connected to the body portion 12.

It is to be understood that the closure cap 10, as illustrated in FIG.1, is only partially formed. It is further to be understood that theclosure cap 10 is formed from a flat blank by a series of punchingoperations by other die sets which may be mounted within a single punchpress and simultaneously actuated.

In accordance with this invention, further operations are performed onthe closure cap 10, as illustrated in FIG. 1, by compound, reciprocatingpunch and die sets which include an upper die set 21 and a lower die set22. The die set 21 includes a punch 23 while the die set I 22 includes acooperating die center 24. The punch 23 is suitably connected to the ramof a punch press and the die center 24 is suitably mounted on the punchpress platen.

The die center 24 is particularly configurated to provide adequatesupport for the closure cap 10 during both the knurling and perforatingoperation which is performed by the die sets 21 and 22. The die center24 includes a base portion 25 which is of a configuration to be snuglyreceived within the skirt extension 14.

A central part of the die center 24 is identified by the numeral 26 andis of a configuration to support the lower part of the skirt extension13 during the combined knurling and perforating operation. The upperpart of the die center 24 is configurated to cooperate with the punch23in the perforating step and will be described in more detailhereinafter. The die center 24 terminates in a top wall 27 which isengaged by the underside of the end panel 17 and serves to axiallyposition the closure member 10.

The lower die set 22 also includes a draw ring 28 which is telescopedover the die center 24 and is mounted for floating movement relativethereto in a conventional manner for cooperation with the punch 23.

The punch 23 is of a generally cylindrical configuration and includes acylindrical body portion 30 and has telescoped in the upper portionthereof a knock out 31 which is suitably separately supported by a rod32. The body portion 30 is of. an internal diameter to be freely passedover in closely adjacent relation the skirt portion 13 of the closurecap 10. The body portion 30 terminates in a lower portion 33 of anincreased internal diameter and internally configurated to cooperatewith the die center 24 in shaping the skirt extension 14. The increasedinternal diameter of the lower portion 29 results in the body portion 30having a sharp annular corner which functions as an annular shearingedge 34.

The underside of the knock out 31 terminates in a lower surface 35 whichopposes the top wall surface 27 of the die center 24 and in cooperationtherewith supports the end panel 17 of the closure cap 10. The knock out31 also has an inner generally frusto-conical surface 36 extendingradially outwardly and downwardly from the undersurface 35 for engagingand supporting the stepped wall portion 18 of the closure cap 10.

With particular reference to FIGS. 4, 5 and 6, it will be seen that theupper portions of the punch 23 and the die center 24 are configurated soas to knurl the upper portion of the body part 13 as the punch 23axially telescopes over the die center 24. In order to properly supportthe stepped end wall portion 18 of the closure cap, the upper part ofthe die center 24 is of a stepped configuration as at 37. Below thisportion of the die center 24 and above the central part 26 of the diecenter 24, the upper part of the die center 24 is circumferentiallyrecessed and is in the form of a plurality of circumferentially spacedprojections 38 and recesses 40, as is best shown in FIG. 5. Theprojections 38 are part cylindrical in configuration and terminate inupper corners 41 which are opposed to the surface 36 of the knock out 31and cooperate therewith to support the lower part of the stepped endwall portion 18 of the closure cap.

Those parts of the die center 24 which define the recesses 40 extend upabove the corners 41 and are disposed radially inwardly of the corners41 in the form of corners 42 which also cooperate with the surface 36 ofthe knock out 31 to support the stepped end wall portion 18 of the'closure cap. This is clearly shown in FIGS. 4 and 6.

It will be readily apparent from the foregoing that the die center 24 isconfigurated to permit the radially inwardly directed deformation of theupper part of the closure cap 10, including portions of the stepped endwall portion 18 in order to effect the knurling of the upper part of theclosure cap. In order to effect the knurling by an endwise relativemovement of the punch 23 and the die center 24, as is best shown inFIGS. 1, 2 and 5, the punch 23 is provided with internalcircumferentially spaced projections 43 which are part circular in crosssection. Each one of these projections 43 terminates in a lower roundedcorner 44, as is best shown in FIG. 4. As is best shown in FIG. 5, eachprojection 43 is radially aligned with a recess 40 in the die center 24.

It will be readily apparent from FIGS. 4, 5 and 6 that during theinitial telescoping of the punch 23 over the die center 24, there is nofurther forming of the partially formed closure cap 10, as illustratedin FIG. 1. However, after the body portion 30 has telescoped over thebody part 13 of the closure cap 10 sufficiently to cooperate with thecentral part 26 of the center 24 to support the upper part of the bodypart 13 of the closure cap against radial outward deformation, therounded lower ends 44 of the projections 43 come into contact with theperipherally outer parts of the stepped side wall portion 18 and effectan initial inward and downward deflection thereof at circumferentiallyspaced points. As the punch 23 and the die center 24 continue totelescope, the projections 43 progressively force the metal of the upperportion of the closure cap into the recesses 40 in the manner shown inFIG. 5. At the same time, the metal of the closure cap is drawn aboutthe projections 38 with the end result being that the upper part of theclosure cap 10, in transverse section, is of a sinisoidal configurationor is knurled. The knurling of the closure cap 10 is illustrated in FIG.8 and is identified by the numeral 45.

It is also to be noted from FIG. 4 that the bottom of each recess 40 isdefined by a downwardly and outwardly sloping shoulder 46 whichcooperates with the rounded lower end of each projection 43 to providefor a smooth transition of the knurling 45 back into the cylindricalbody part 13 of the closure cap 10, as is best illustrated in FIGS. 4and 8.

It is to be understood that prior to the completion of the knurlingoperation, perforation of the lower part of the closure cap is initiatedin a manner to be described hereinafter. The knurling operation iscompleted simultaneous with the completion of the perforating operation.

With particular reference to FIGS. 4 and 7, it will be seen that thecentral part 26 of the die center 24 merges into the base portionthereof by a generally conical shoulder 47. The shoulder 47 is locatedbelow the shoulder 15 of the closure cap 10 when the closure cap 10 hasthe end panel 17 thereof fully seated on the top wall 27 of the diecenter 24.

At a number of circumferentially spaced points, the die center 24 isprovided with rounded seats 48 which project up from the shoulder 47 andare of a configuration and location to engage and support the shoulder15. The seats 48 are narrow in circumferential extent.

With particular reference to FIG. 4, it will be seen that when the punch23 approaches a position of almost complete telescoping with respect tothe die center 24, the shear edge 34 thereof engages the shoulder 15 ofthe closure cap 10 supported on the die center 24 with the shear edge 34engaging the shoulder 15 generally at the midpoint thereof. At this timeit is also pointed out that the shoulder 15 is of a configuration sothat the skirt extension 14 is disposed radially outwardly of the bodypart 13 a distance which is slightly greater than the thickness of themetal forming the closure cap 10. It will be readily apparent from FIG.4 that the shear edge 34, as it moves downwardly with respect to theshoulder 15 with the upper portion of the closure cap 10 beingrestrained against downward movement by the die center 24, shears theshoulder 15 in half. As the shoulder 15 of the closure cap 10 is shearedin half, the skirt extension 14 and the lower half of the shoulder 15are moved downwardly by the punch 23. During this movement, the skirtextension 14 is supported by the flange 16 which is seated on the drawring 28 which moves downwardly therewith. The lower half of the shoulder15 finally seats on the shoulder 47 of the die center 24.

It is to be understood that the shearing of the shoulder 15 by the shearedge 34 is not circumferentially complete, but is interrupted atintervals. As is shown in FIG. 7, the undersurface of the body portion30 is interrupted by radially extending slots 49 which are aligned withthe seats 48. Thus, in the areas of the seats 48 the shear edge 34 isinterrupted and the shoulder 15 is not severed. However, as the skirtextension 14 is moved downwardly by the punch 23 after the interruptedsevering of the shoulder 15 occurs, there will be a stretching of theunruptured portions of the shoulder 15 in a generally axial direction.The metal remaining along the shoulder 15 will be in the form ofintegral connecting tabs which are identified by the numeral 50 in FIGS.4, 7 and 8.

It will be readily apparent that the action of the punch 23 is more thana severing action inasmuch as the punch 23 moves the severed materialaxially downwardly. Thus, the function of the die set is more thanmerely a severing operation, but is in a true sense of the word aperforating operation.

It is to be noted that in the shearing of the shoulder 15 of the closurecap 10, the configuration of the severed halves of the shoulder remainwith the result that in the final closure cap, as is best illustrated inFIGS. 4 and 8,.between the tabs the lower edge of the body part 13 isreinforced by an outwardly directed flange 51 and the upper edge of thepilfer-proof band, which is identified by the numeral 52, is reinforcedby an inwardly directed flange 53. The flanges 51 and 53 oppose eachother on opposite sides of the associated perforation 54 and the flange53 and the adjacent portion of the band 52 serves to protect the rawedge of the flange 51 until the closure cap is removed from anassociated container.

Referring once again to FIGS. 1 through 5, it will be seen that theprojections 43 are not integrally formed with the punch 23, but are inthe form of separately formed pins 55. Each pin 55 is seated in a bore56 formed in the die punch 23. By separately froming the pins 55, whichare the components of the die set 21 subject to wear, the pins 55 may beformed of a hardened material so as to be long lasting. Also, it isfeasible to removably retain the pins 55 within their respective bores56 in any desired manner.

After the formation of the closure cap has been completed, the end wallportion 11 of the closure cap is provided with a suitable lining 60 inany desired manner. Thereafter, the closure cap 10 is subjected to atrimming die set 61 which includes a die center 62 of a configuration tosupport the pilfer-proof band 52, and a trimming member 63 which is of asize to closely surround the pilfer-proof band 52 and support the samewhile cooperating edge portions of the die center 62 and the trimmingmember 63 shear off the flange 16, as is best shown in FIG. 8.

It will be readily apparent that by providing suitable tooling of thepunch and die type which will effect the formation of the necessaryknurling and cut the necessary perforation to define the pilfer-proofband, the manufacturer of the closure caps may be accomplished by muchsimpler tooling all of the same type. The die sets which arespecifically disclosed herein may be incorporated in a punch press withsimilar types of die sets for the progressive blanking, drawing, knurlformation and perforating.

Although only a preferred embodiment of the invention has beenspecifically illustrated and described herein, it is to be understoodthat minor variations may be made in the apparatus, method and closurecap formed therewith without departing from the spirit and scope of theinvention, as defined by the appended claims.

The embodiments of the invention in which an exclusive property orprivilege is claimed are defined as follows:

1. A die forming apparatus for perforating a closure cap skirt andforming thereon an integral pilfer-proof band, said die formingapparatus including a first die member for receiving and internallysupporting a closure cap having an end panel and an outwardly enlargedlower skirt portion connected to the remainder of the closure cap by asingle thickness peripheral shoulder, said first die member being of aconfiguration to be received within a closure cap in close fittingrelation with respect to both the enlarged skirt portion and theremainder thereof with the end panel seated thereon, and a second diemember having means for shearing a closure cap through the shoulderthereof along peripherally elongated and spaced areas upon relativeendwise movement of said die members.

2. The die forming apparatus of claim 1 wherein the relative movement ofsaid die members is such that said second die member is removable beyondthe point of 5 shoulder shearing for axially separating sheared butinterconnected shoulder sections.

3. The die forming apparatus of claim 2 wherein said first die memberhas means for supporting and reshaping severed but still connected lowerportions of a closure cap shoulder after the severing and axialdisplacement thereof.

4. The die forming apparatus of claim 1 wherein said first die memberhas peripherally spaced support means for engaging and supporting aclosure cap shoulder during the shearing thereof, said shearing meansbeing interrupted in radial alignment with said support means.

5. A method of forming a pilfer-proof band on a closure cap comprisingthe steps of forming a closure cap having an axially elongated skirt ofwhich a lower portion is of an increased diameter and is connected tothe remainder of said skirt by a single thickness shoulder, internallysupporting said closure cap, and then in a single simultaneous stepshearing said shoulder along peripherally elongated and spaced areaswhereby said lower skirt portion becomes a pilfer-proof band secured tothe remainder of said closure cap by peripherally spaced tabs.

6. The method of claim 5 wherein said lower skirt portion is axiallydisplaced and said severed shoulder portions are axially displaced.

7. The method of claim 6 wherein said tabs are axially elongated duringthe displacement of said lower skirt portion.

1. A die forming apparatus for perforating a closure cap skirt andforming thereon an integral pilfer-proof band, said die formingapparatus including a first die member for receiving and internallysupporting a closure cap having an end panel and an outwardly enlargedlower skirt portion connected to the remainder of the closure cap by asingle thickness peripheral shoulder, said first die member being of aconfiguration to be received within a closure cap in close fittingrelation with respect to both the enlarged skirt portion and theremainder thereof with the end panel seated thereon, and a second diemember having means for shearing a closure cap through the shoulderthereof along peripherally elongated and spaced areas upon relativeendwise movement of said die members.
 2. The die forming apparatus ofclaim 1 wherein the relative movement of said die members is such thatsaid second die member is removable beyond the point of shouldershearing for axially separating sheared but interconnected shouldersections.
 3. The die forming apparatus of claim 2 wherein said first diemember has means for supporting and reshaping severed but stillconnected lower portions of a closure cap shoulder after the severingand axial displacement thereof.
 4. The die forming apparatus of claim 1wherein said first die member has peripherally spaced support means forengaging and supporting a closure cap shoulder during the shearingthereof, said shearing means being interrupted in radial alignment withsaid support means.
 5. A method of forming a pilfer-proof band on aclosure cap comprising the steps of forming a closure cap having anaxially elongated skirt of which a lower portion is of an increaseddiameter and is connected to the remainder of said skirt by a singlethickness shoulder, internally supporting said closure cap, and then ina single simultaneous step shearing said shoulder along peripherallyelongated and spaced areas whereby said lower skirt portion becomes apilfer-proof band secured to the remainder of said closure cap byperipherally spaced tabs.
 6. The method of claim 5 wherein said lowerskirt portion is axially displaced and said severed shoulder portionsare axially displaced.
 7. The method of claim 6 wherein said tabs areaxially elongated during the displacement of said lower skirt portion.